What should you do in this kind of visibility?

You answered correctly. In situations with limited visibility like this, you must reduce your speed to be able to react to any hazards that may appear suddenly. You should also keep towards the right-hand edge of the road to avoid the risk of colliding with oncoming vehicles, especially if their lights cause glare or reduce your ability to see the road clearly. Switching on your main beam lights is not appropriate when there is oncoming traffic, as it would dazzle other drivers. So, the correct actions are reducing your speed and positioning your car to the right. This keeps everyone safer in conditions with poor visibility.